1. Field of the Invention
The present invention relates to a contact sheet having spiral contactors serving as elastic contactors, and to a connecting device including the contact sheet.
2. Description of the Related Art
U.S. Pat. No. 7,080,993 discloses a contact sheet having spiral contactors. The spiral contactors each include a supporting portion provided along an outer rim of an opening provided in the sheet, and a spiral deforming portion extending from the supporting portion toward the center of the opening. The spiral contactors are arranged in a regular manner. A supporting portion of one of the adjacent spiral contactors has a concave portion at one side thereof, and a part of a deforming portion of the other spiral contactor is located in the concave portion.
U.S. Pat. No. 4,893,172 does not describe a spiral contactor, but discloses a flat spring. A spiral connecting portion of the flat spring is located in an opening provided in an insulation sheet, and connects a terminal of a semiconductor chip and a terminal of a substrate that are respectively provided on the upper and lower sides of the insulating sheet.
In the contact sheet disclosed in the former publication, the distance between the adjacent spiral contactors is decreased in one direction (row direction) in which the concave portion and the spiral contactor partly located in the concave portion are arranged, and this increases mounting density in the direction. However, the distance between the adjacent spiral contactors is not decreased in the column direction orthogonal to the row direction. For this reason, it is difficult to increase the mounting density over the entire contact sheet.
In the latter publication, a supporting portion of one flat spring is provided in a region surrounded by four openings that are adjacent in the row direction and the column direction. However, the area of the supporting portion provided on the insulating sheet is smaller than the area of the region surrounded by the four openings. For this reason, a force for supporting the connecting portion of the flat spring is weak, and it is difficult to increase the spring constant of the flat spring.